The basic screen printing technique for the glass display screen of a CRT involves exposure of a light-sensitive colloid. The exposed area becomes insoluble and remains after development. On the other hand, in the black matrixing approach designed to improve color contrast, the matrix printing requires a process that has the reverse polarity because the matrix openings should be clear with the surrounding area black. This phosphor screening process involves the application of a photoresist applied to the display screen's inner surface. The photoresist typically includes polyvinyl pyrrolidone (PVP), 4,4"-diazidostilbene-2,2" disulfonic acid, disodium salt and water. Adhesion of this photoresist to the CRT glass faceplate has always been a problem giving rise to reduced production yields. To overcome this problem, polyvinyl alcohol (PVA) is added to the photoresist material. Addition of the PVA provides two benefits. First, adhesion between the photoresist and the glass faceplate is substantially improved. Secondly, addition of the PVA to the photoresist serves to depress the oxygen level, resulting in a decrease in the time required for the photoresist to be exposed to ultraviolet light for curing. However, because of an incompatibility between PVP and PVA, the addition of the PVA to the photoresist material makes it more difficult to apply the photoresist to the glass faceplate in the form of a thin film having a uniform thickness.
The present invention addresses the aforementioned problems encountered in the prior art by allowing for the addition of PVA to a photoresist coating solution providing a high degree of adhesion of the coating to a glass faceplate while allowing the coating to be applied to the faceplate in the form of a thin film of highly uniform thickness.